Nonlinear frequency modulated gyroscope

Abstract

A nonlinear frequency modulated gyroscope includes a degenerate-mode mechanical resonator, positive feedback circuits, a temperature control component, and a gyroscope controller. The degenerate-mode mechanical resonator with two or more modes are coupled via a Coriolis effect. The positive feedback circuits for each mode of the degenerate-mode mechanical resonator include an analog or digital automatic gain control that maintains oscillations of each mode at a constant amplitude. The temperature control component includes a sensor and heating elements. The gyroscope controller is an application-specific integrated circuit, a field programmable gate array, or microcontroller. The degenerate-mode mechanical resonator, the positive feedback circuits, and the temperature control component are subsystems of the nonlinear frequency modulated gyroscope.

What is claimed is: 
     
       1. A nonlinear frequency modulated gyroscope, comprising:
 a degenerate-mode mechanical resonator with two or more modes, wherein the two or more modes are coupled via a Coriolis effect; 
 positive feedback circuits for each mode of the degenerate-mode mechanical resonator, wherein the positive feedback circuits include an analog or digital automatic gain control circuit that maintains oscillations of each mode at a constant amplitude; 
 a temperature control component, wherein the temperature control component includes a temperature sensor and heating elements; and 
 a gyroscope controller, wherein the gyroscope controller is an application-specific integrated circuit, a field programmable gate array, or microcontroller; 
 wherein the degenerate-mode mechanical resonator, the positive feedback circuits, and the temperature control component are subsystems of the nonlinear frequency modulated gyroscope. 
 
     
     
       2. The nonlinear frequency modulated gyroscope subsystem of  claim 1 , wherein the positive feedback circuit includes a phase shifter circuit connected to a comparator circuit that adjusts a phase output and an amplitude output of each mode of the degenerate-mode resonator to self-oscillate. 
     
     
       3. The nonlinear frequency modulated gyroscope subsystem of  claim 2 , wherein the phase shifter circuit includes an active all-pass filter, a passive phase shifter, or a high-pass filter. 
     
     
       4. The nonlinear frequency modulated gyroscope subsystem of  claim 2 , wherein the comparator circuit includes an attenuator to adjust the amplitude output of the nonlinear frequency modulated gyroscope to a value to maintain a target amplitude. 
     
     
       5. The nonlinear frequency modulated gyroscope subsystem of  claim 4 , wherein the comparator receives a voltage ranging from about −5 V to about 5 V and the value is equal to or great than 0 V. 
     
     
       6. The nonlinear frequency modulated gyroscope subsystem of  claim 2 , wherein the analog or digital automatic control circuit adjusts the amplitude output of the comparator circuit by using a proportional-integral (PI) controller. 
     
     
       7. The nonlinear frequency modulated gyroscope subsystem of  claim 1 , wherein the temperature control component is attached to an interface electronics board or a chip carrier. 
     
     
       8. The nonlinear frequency modulated gyroscope of  claim 1 , wherein the temperature sensor is a platinum resistance temperature device or a thermistor. 
     
     
       9. The nonlinear frequency modulated gyroscope subsystem of  claim 1 , wherein the heating elements are power resistors. 
     
     
       10. The nonlinear frequency modulated gyroscope subsystem of  claim 1 , wherein the degenerate-mode mechanical resonator is attached to a chip carrier that is connected to an interface electronics circuit board. 
     
     
       11. The nonlinear frequency modulated gyroscope subsystem of  claim 1 , wherein the degenerate-mode mechanical resonator is enclosed in a vacuum chamber. 
     
     
       12. The nonlinear frequency modulated gyroscope subsystem of  claim 1 , wherein the degenerate-mode mechanical resonator includes a plurality of shaped combs with control loops in an amount equal to a number of modes to maintain a mean or an average frequency of each mode at a constant value or the plurality of shaped combs with at least one control loop to maintain a difference in a mean or an average modal frequency at a constant value. 
     
     
       13. A nonlinear frequency modulated gyroscope system, comprising:
 a degenerate-mode mechanical resonator, wherein at least two of the modes of the degenerate-mode mechanical resonator can be coupled via a Coriolis effect; 
 positive feedback circuits to match with every mode of the degenerate-mode mechanical resonator, wherein the positive feedback circuits include an analog or digital automatic gain control that maintains oscillations of each mode at a constant amplitude; 
 a temperature control component, wherein the temperature control component includes a sensor and heating elements; and 
 a gyroscope controller, wherein the gyroscope controller is an application-specific integrated circuit, a field programmable gate array, or microcontroller; 
 wherein the degenerate-mode mechanical resonator, the positive feedback circuits, and the temperature control component are subsystems of the nonlinear frequency modulated gyroscope system. 
 
     
     
       14. The nonlinear frequency modulated gyroscope system of  claim 13 , wherein the positive feedback circuit includes a phase shifter circuit connected to a comparator circuit that adjust a phase output and an amplitude output of each mode of the degenerate-mode resonator to self-oscillate. 
     
     
       15. The nonlinear frequency modulated gyroscope system of  claim 14 , wherein the comparator includes an attenuator to adjust the amplitude output of the nonlinear frequency modulated gyroscope to a value to maintain a target amplitude.